Fluid heater casing



Jan. 29, 1946.

.J. F. HARVEY FLUID HEATER CASING Filed Feb. 18, 1945 INVENTOR. .fO/m FHam/e A TTORNE Y Patented Jan- 29, 1946 FLUID HEATER CASING John F.Harvey, Akron, Ohio, assignor to The Babcock & Wilcox Company,Rockleigh, N. J., a corporation of New Jersey Application February 18,1943, Serial No. 476,279

8 Claims.

.The present invention relates in general to the construction ofgas-tight fluid heater casings adapted to enclose a space containing agaseous fluid under pressure; and more particularly, to a sectionalcasing construction for a marine steam boiler within which-air forcombustion purposes is circulated under a relatively high pressure.

The main object of my invention is the provision of a fluid heatercasing of the character described which is characterized by itsrelatively high structural strength, gas tightness, and low heat loss byconduction. A further and more specific object is the provision of agas-tight structural joint for a fluid heater casing, including asupporting structural member constructed to substantially reduce theheat flow from the inner to the outer side of the joint without anymaterial change in the strength of the supporting member. 7

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawing and descriptivematter in which I have illustrated and describedpreferred embodiments ofmy invention.

- Of the drawing:

Fig. 1 is a perspective view, partly broken away and .in section, of amarine steam boiler casing constructed in accordance with my invention;

Fig. 2 is a vertical section of a sectional casing joint illustrating amodified form of my invention; and

Fig. 3 is a planview of the structural supporting member shown in Fig.2.

In the drawing I have illustrated my invention as employed in theconstruction of a steam boiler sectional casing of the general typeillustrated in U. S. Patent No. 2,251,014 for enclosing a space throughwhich air for the fuel burners is circulated under a relatively highpressure. In Fig. 1

I have shown the boiler casing as formed by a plurality of sections l0,each of which consists of two dished inner and outer panels II and I 2of thin sheet metal, such as gage sheet steel. The panels ll, l2preferably have similar boundary dimensions with their edge flanges l Iand I2 respectively facing outwardly and slightly spaced apart. Thepanels are held in this arrangement, while minimizing the outward heatflow from the inner flange II to the outer flange I 2*, by tack welds l3at spaced points along their length. The

space between the panels is packed with a suitable heat insulatingmaterial 15, such as uncalcined diatomaceous earth. 1

Adjacent casing sections ID are assembled by suitably connecting theadjoining outer flanges I2 to provide a gas-tight joint therebetween.When the length of the connected flanges is long or the gas pressurewithin the casing relatively high, it is necessary to provide astructural load carrying member connecting the casing sections It] to aninner structural member or casing It. If the usual type of structuralsupporting member is placed between the edge flanges of adjoining casingsections, it would form an excellent heat conductor through the casing,nullifying the insulating efiect of the heat insulating material l5 andtack welded flange construction and tending to overheat the outerflanges l2.

In accordance with my invention, a structural supportin member isarranged between the edge flanges of adjoining casing sections l0 andspecially shaped to maintain a gas-tight joint while minimizing theamount of heat conducted through the structural member to the outer sideofthe casing. In the construction shown in Fig. 1,-the

structural supporting member is in the form of a flat plate or bar 20positioned between and substantially coextensive with the flanges H andI2. Tabs 2| project inwardly at spaced points along the inner edge ofthe bar 20 for connecting the bar 20 to the inner casing or structuralsup-; port I 6 through tie bars 22. The bar 20 has elongated slots 23above the adjacent edges of the flanges ll and I2 and particularly thetack welded portions thereof except for narrow short connecting neckportions 24 at spaced points. The cut away portions are thus confined tothe region of the neutral axis of the bar 20, and accordingly have onlya slight reducing effect on the strength of the'bar. The bar is tightlysecured along its outer edge portion to the outer edge flanges l2 bybolt connections 25 to form a gas-tight joint between the casingsections. Brass sheathed asbestos packing strips can be used between thebar 20 and the outer edge flanges I 2 to minimize gas leakage. The heatflow through the neck portions 24 is quite low and of substantially thesame order as through the insulated panel portions. The slots 23 form ineffect heat traps at the corresponding portions of the joint, whilereducing'the amount of material required for the supporting member.

In the modification shown in Figs. 2 and 3, the structural supportingmember for the edge flange j t is formed by parallel inner and outerbars 26 and 21 respectively having connecting neck portions 2 3 formedby fusion welding the bars 26 and 21 together at spaced points, formingin effect slotted portions 23 along the neutral axis of the compositebar. The bar construction and arrangement are otherwise similar to thatof Fig. 1.

Whil in accordance with the provisions of the statutes I haveillustrated and described herein the best forms of the invention nowknown to me,

those skilled in the art will understand that changes may be made in theform of the apparatus disclosed without departing from the spirit of theinvention covered by my claims, and that certain features of myinvention may sometimes be used to advantage without a corresponding'use of other features. I

I claim: 7 1. A fluid heater casing comprising a pluralit of heatinsulated casing sections, each having inner and outer spaced apartsheet metal panels and heat insulating material in the space betweensaid panels, and a structural supporting member arranged betweenadjoining sections, said sup porting member having slots extendingsubstantially along and occupying a major portion of its length andforming spaced connecting neck portions between said sections tominimize the heat flow through said supporting member.

2. A fluid heater casing comprising a plurality of heat insulated casingsections, each having inner'and outer spaced apart sheet metal panelsand heat insulating materialin the space between said panels,'and astructural supporting member arranged between adjoining sections andconnected thereto to form a gas-tight joint therebetween, saidsupporting member having slots extending substantially along its neutralaxis and forming spaced connecting neck portions between 'said sectionsto minimize the heat flow through said supporting member.

3. A fluidheater casing comprising a plurality 4. A fluid heater casingcomprising a plurality of heat insulated'casing sections, each havinginner and. outer sheet metal panels with spaced apart out-turned edgeflanges connected at spaced points and heat insulating material in thespace between said panels, and a flat structural supporting memberarranged between the edge flanges of adjoining sections, said supportingmember having slots extending substantially along the edges of saidconnected flanges and forming spaced connecting neck portions betweensaid sections to minimize the heat flow'through said supporting member.7 V

5. A fluid heater casing comprising a plurality of heat insulated casingsections, each having inner and outer sheet metal panels with spacedapart out-turned edge flanges connected at spaced points and heatinsulating material in the space between said panels, and a structuralsupporting member arranged between the edge flanges of adjoiningsections and connected to the edge flanges V of said outer panels toform a gas-tight joint therebetween, said supporting member having slotsextending along the edges of said connected flanges and formingspaced-connecting neck portions between said sections to minimize theheat flow through said supporting member.

6. A fluid heater casing comprising a plurality of heat insulated casingsections, each having inner and outer sheet metal panels with spacedapart out-turned edge flanges tack welded together at spaced points andheat insulating material in the space between said panels, and a flatstructural supporting member horizontally arranged between thehorizontal edge flanges of adjoining sections and connected tothehorizontal edge flanges of said outer panels to form a, gastightjoint therebetween, said supporting member having slots extendingsubstantially along its neutral axis and forming spaced connecting neckportions between said sections to minimize the heat flow through saidsupporting member.

'7. A fluid heater casing comprising a plurality of heat insulatedcasing sections, each having inner and outer sheet metal panels withspaced apart out-turned edge flanges connected at spaced points andheatinsulating material in the space between 'said panels, a structuralsupporting member arranged between the edge flanges of adjoiningsections, said supporting member having slots extending along the edgesof said connected flanges and forming spaced connecting neck portionsbetween said sections to minimize the heat flow through said supportingmember, an inner support, and means for connecting the inner side ofsaid supporting member to said support.

8. A fluid heatercornprising .a plurality of heat insulated casingsections, each having inner and outer sheet metal panels with spacedapart out turned edge flanges tack welded together 'atspaced points andheat insulating material in the space between said panels, a flatstructural supporting member horizontally arranged between the edgeflanges of adjoining sections and connected to the edge flangesof saidouter panels to'form a gastight joint therebetween, said supportingmember having slots extending substantially along its neutral axis andforming spaced connecting neck portions between said sections tominimize the heat flow through said supporting member, an inner support,and means forconnccting the inner side of said supporting member to saidsupport.

4 JOHN F. HARVEY.

